From its source, the Lessard River flows almost to the limit of the former Sainte-Marie seigneury, over 14.4 kilometres (8.9 mi) divided into the following segments: The "Chute à Corinne" is located about three kilometers upstream from its confluence; then the river flows in a narrow valley between hills made of finiglacial materials, characterizing this part of Beauce.

This watercourse was initially designated "Rivière du Tabord" according to a document of 1785, an enigmatic designation which perhaps recalls mount Tabor or Tabor, mountain of Lower Galilee where the transfiguration of Christ took place.

The current name evokes the Lessard families who were numerous to own lots of land near this watercourse.

As early as 1819, the two lords Taschereau, Sainte-Marie and de Jolliet, built a flour mill on the land of François Lessard.

[2] The toponym "rivière Lessard" was made official on December 5, 1968, at the Commission de toponymie du Québec.